Dust preventative and method of laying dust



Patented July 5, 1938 rATEr .FlE

DUST PREVENTATIVE 'AND METHOD OF LAYING DUST Benjamin F. Hunter, Pittsburgh, Pa assignor to Gulf Research & Development Company, a corporation of Delaware No Drawing. Application November 1, 1935,

Serial No. 47,903

2 Claims.

Thisinvention relates to dust preventatives; and it comprises as a liquid spraying agent for laying and binding the soil dust in open play grounds andthe like a refined petroleum oil distillate of low volatility and low viscosity containing a small quantity, usually of the order of l per cent or less, of a water-insoluble but hygroscopic or'water-absorbing fatty derivative having a demulsifying action upon the oil and giving the dust-laying agent the property of resisting removal by rain water, suitable substances for this purpose being the sod oil derived from leather tawing, degras from the same source are aqueous solutions of calcium chlorid and heavy petroleum oils of asphalt base. The former is effective in preventing dust by reason of the strong hygroscopic property of calcium chlorid but has the disadvantage of being readily leached from the road by rain. The asphaltic oil is more permanent and resistant to rain water but is unpleasant because of its odor and color 7 staining.

The color and odor of asphaltic petroleum are associated with the constituents giving a certain permanence to the material and to its effectiveness in preventing dust. The color and odor cannot be removed from the oil without sacrificing effectiveness and permanence. In the present invention a dust laying liquid stabilized against removal from the soil by rain and substantially without color and odor is an achieved object. This liquid has particular utility in laying the dust of play grounds and the like where the odor and color of the usual road oils are objectionable.

For spraying play grounds to prevent dust the road oils containing asphalt or heavy hydrocarbons are efiective in laying dust but the color and odor of such oils are quite objectionable. But the use of oil free of asphalt and of tar has not been practicable because of the tendency to emulsify in rain water and to be washed away. I have succeeded in utilizing refined oils free of asphaltic and tarry matter and in inhibiting loss of the oil from the play grounds in rainstorms. A play ground spraying oil substantially colorless and odorless thus becomes practically available.

I have found that a dust spraying oil equally as effective and permanent as the crude or heavy petroleum oils can be formed by incorporating with'a refined petroleum oil distillate, which may be practically colorless and odorless, a modicum or extremely small quantity of a fatty substance which is practically insoluble in water but which has the power to absorb water and to inhibit or prevent the emulsification of the petroleum oil in water. I can thus in effect refine the color and odor from crude or heavy oil and restore the permanence or resistance to emulsification in rain water by a small addition of a fatty demulsifying agent.

Among the fatty substances that I have found particularly effective in inhibiting emulsification and loss of refined petroleum dust laying oils in rain water is the degras obtained either in the production of leather by oil tawing or in the scouring of wool with soap. The sod oil obtained in making chamois skin is also useful. Addition to the refined petroleum oil of about one per cent of degras or sod oil is usually sufficient to protect the petroleum oil when used as a dust spray against the tendency to emulsify and be carried away in rain water. refined hydrous wool fat has also been found to be an effective demulsifying agent. A content of Wool fat degras even as low as 0.02 per cent has been found effective. The petroleum oil is thus stabilized in its dust laying and binding action.

In general, the water-insoluble or metal soaps which have the property of emulsifying water in oil are useful addition agents in refined petroleum oils for use as dust sprays. Lime soaps precipitated from alkali soap solutions are effective. Of the soaps, the oleates, palmitates and stearates are all suitable. I have found precipitated aluminum oleate to be particularly effective. A content of -0.01 to 0.1 per cent of aluminum oleate in petroleum oil is usually sufficient.

The fatty material added to petroleum oil has the property of. breaking emulsions of oil in water and thus of preventing or greatly minimizing the loss of the oil due to emulsification in rain water. The fatty material is dissolved or dispersed in the oil and by a surface action in the dust largely prevents emulsification of the oil. Thus the Lanolin, a

Lil

fatty derivative contained in the oil may be said to have a demulsifying action or effect.

For the dust laying liquid any relatively nonvolatile or high boiling petroleum distillate may be used. It is advantageous to utilize an oil fraction of moderately low viscosity. The distillate may be refined by the usual sulfuric acid treatment followed by alkali washing, or the refining may be by other equivalent methods. Any desired freedom from color and odor is attainable in the refining treatment. A satisfactory petroleum oil is a refined distillate of 22 to 31 degrees A. P. I. gravity having a S. U. V. viscosity not under 50 seconds at 100 F., a color not above 4 on the N. P. A. scale and only a faint petroleum odor. Such a refined oil is substantially free of asphaltic and of tarry matter. With the refined oil is admixed the small amount, not greater than about 1 per cent of degras, lanolin, soap or other fatty derivative acting as a demulsifier. A hydrous fatty derivative addition in small quantity as described gives the oil a pleasing milky appearance.

For spraying play grounds an addition to the oil of a germicide is advantageous. For this, a cresol or cresylic acid in small proportions is suitable. About 0.1 to 0.2 per cent dichlorpentane added to the oil acts as a germicide and gives a pleasant odor.

A spraying oil of characteristics and composition as above described, with a single application to a playing ground, has given excellent results in preventing dust during a years season of. use.

The good results were obtained at a relatively low cost.

What I claim is:-

1. A manufactured material comprising a liquid spraying agent for use in laying dust on open play grounds and like areas exposed to the weather, said liquid being a substantially colorless and odorless asphaltand tar-free refined petroleum oil distillate of 22 to 31 degrees A. P. I. gravity of low viscosity and low volatility and having added thereto and dispersed therein a small quantity of hydrous degras sufiicient to inhibit emulsification and loss of the oil in rain water.

2. A method of laying dust in open play grounds and like areas exposed to the weather which comprises spraying the ground with a substantially colorless and odorless asphaltand tarfree refined petroleum oil distillate of 22 to 31 degrees A. P. I. gravity of low volatility and having added thereto and dispersed therein a small quantity of hydrous degras acting to inhibit emulsification and loss of. the oil in rain water.

BENJAMIN F. HUNTER. 

